The rumor persists that Amelia Earhart was spying on Japan for her good friend, President Franklin Roosevelt. A new expedition to find her downed aircraft may finally put to rest some of the wild theories about the aviatrix.

Was Amelia Earhart a US spy? That’s one of the persistent rumors about the famous aviatrix, who disappeared in the Pacific 75 years ago on a dangerous leg of her planned around-the-world flight.

There are many versions of this story, but most share a basic outline: Earhart allegedly was keeping an eye on Japanese activities for her good friend, President Franklin Roosevelt. Her famous Lockheed Electra 10E might even have been equipped with secret cameras. Captured by Japanese forces following a crash, she was spirited to the island of Saipan, where she may or may not have survived World War II. Some even claim she was one of the women who provided the voice of Japanese propaganda broadcaster Tokyo Rose.

The mystery of the disappearance of Amelia Earhart and navigator Fred Noonan is getting renewed attention this week due to Secretary of State Hillary Rodham Clinton’s backing of a new search for their downed aircraft. The International Group for Historic Aircraft Recovery (TIGHAR) this July will mount an expedition to a South Pacific coral speck now known as Nikumaroro, in the Republic of Kiribati. A modern examination of an old photo taken of the site shows what might be aircraft landing gear protruding from water offshore, according to TIGHAR.

“Not since George Washington chopped down the cherry tree has a historical figure been the subject of more myth and legend than has Amelia Earhart,” concludes TIGHAR in a section of its website devoted to debunking such confabulations.

As TIGHAR points out, no US government documents supporting the Earhart-spy story have ever been found. The FDR presidential library is silent on the subject, as are Army and Navy Intelligence files from World War II. That hasn’t stopped the spy theorists, though: They see absence of such files as proof that a government conspiracy is covering up the truth.

In 1943, a thinly fictionalized movie of Earhart’s life titled “Flight for Freedom,” starring Rosalind Russell and Fred MacMurray, portrayed her as flying over Japanese territory in a secret US mission prior to her disappearance. That’s the basis for many of the rumors, according to TIGHAR. Since then, several books have purported to prove the plot of this movie, including “Requiem for Amelia,” published in 1966 and written by former Navy officer Paul Briand, and “Lost Star,” a 1994 effort by Randall Brink and published by W.W. Norton.

Most of the spy theories start with the recollection of a US serviceperson, heard somewhere in the Pacific theater during World War II, and then build speculation upon this foundation. As it happens, Amelia Earhart’s FBI files are now public, and they contain FBI investigations of many of these rumors, none of which the agency established to be true.

For instance, the FBI file contains records of an agency interview of a soldier, name expunged, conducted at Walter Reed Army Hospital in 1944. The soldier says he was stationed in the Philippines prior to Pearl Harbor, and one night was entertained at a local hotel by some Japanese acquaintances.

“He stated the walls of the hotel were extremely thin and he overheard a conversation in English between two Japanese to the effect that Amelia Earhart was still alive and was being detained at a hotel in Tokyo,” reads the FBI report of the interview.

“He stated that he never has been able to forget these remarks,” reads the report.

The soldier in question was a prisoner of the Japanese for much of the war, explaining why he hadn’t come forward sooner. But why were Japanese speaking to each other about such a sensitive subject in English? That is both unlikely and unaddressed by the FBI. The agency did not itself follow up on these allegations – it told the solider the whole thing was the purview of military intelligence, and that was where he should take his recollections.

The FBI file also contains correspondence between agency officials regarding the aforementioned book by Paul Briand, “Requiem for Amelia.” Their main concern seemed to be that certain material referenced in the book was said to come from the FBI, when it hadn’t. They insisted that Briand acknowledge that the material had come from various military intelligence sources, as opposed to the FBI. Why? Perhaps they didn’t want the FBI’s fingerprints on Briand’s assertions. Perhaps they were just being accurate. Nothing in the file indicates that they thought Briand was correct, however.

The FBI records also contain numerous requests from private individuals to J. Edgar Hoover to tell them the truth about Earhart’s activities. On Oct. 14, 1971, the famous FBI chief replied to one inquiry from a resident of Staten Island in New York. He sounds exasperated in the short missive.

“Although I would like to be of assistance in connection with your letter, the FBI does not have any material for distribution concerning Amelia Earhart. She was not the individual known as ‘Tokyo Rose.’ You may be able to find data regarding both of these people in your local library. Sincerely yours, J. Edgar Hoover,” he wrote.